A solar cell is a device that converts solar energy into electricity. Recent developments in solar cell technology have made possible lower manufacturing costs with acceptable energy-conversion efficiency.  Applications not possible before like utilization in fabric or thin-coating to a number of surfaces can now be achieved. Imagine a future with clothing producing solar energy or automobiles, buildings and gadgets getting their power from the sun.

Solar cells have evolved from the first generation single-junction P-N devices to the third generation low-cost thin-film devices. The first generation units, made of crystalline silicon materials, offer energy efficiencies of more than 30% and have a payback period from 5 to 7 years. They are still expensive but accounts for almost 90% of the units sold in the market at present.

Second generation thin-film cells, some of which are made of cadmium telluride or copper indium gallium selenide, were developed to lower production costs of solar cells. These materials are applied as a thin film to sheets of glass or ceramics. This manufacturing technique reduced material mass, which made possible its application to smaller or irregularly shaped devices.  There is not much improvement though to energy efficiency compared to first generation solar cells.  Second generation cells are slowly becoming more common in the market.

The third generation solar cells addressed two concerns - high-manufacturing costs of first generation cells and low energy efficiency of second generation cells. The most popular of the third generation cells is Dye-sensitized solar cells (DSC) that is based on nano-structure technology - optically transparent film of titanium dioxide particles, coated with layer of a charge-transfer dye to sensitize the film for light collection. This technology promises the highest energy-conversion efficiency in the order of more than 40%. These cells were invented by Michael Grätzel and Brian O'Regan at the École Polytechnique Fédérale de Lausanne in 1991, the reason why the cells are called Grätzel cells.

DSCs separate the two functions (photo collection and electron transfer) provided by first and second generation single-junction solar cells. DSCs have three primary parts – an anode glass plate, a cathode metal plate and an electrolyte material sandwiched in-between. The anode is deposited with a thin layer of titanium dioxide (TiO2) that is usually coated to a glass. The plate is then immersed in a mixture of a photosensitive dye and a solvent. Another sheet acts as a cathode, typically platinum metal coated with a thin layer of iodide electrolyte.

This is how it works. Sunlight enters the cell through the transparent glass plate striking the dye on the surface of the TiO2. This will create an excited state of the dye, resulting in the movement of electrons from the dye to the anode. The dye will then strip electrons from the iodide electrolyte to compensate for loss electrons and this process oxidizes the electrolyte into triiodide. The triiodide then recovers its missing electrons by the introduction of electrons from the cathode metal plate.

It can be said that Dye-sensitized solar cell technology is still in its infancy and not yet in commercial deployment. Since DSC cells are made of low-cost materials (TiO2 is widely used as a paint base) and easy to manufacture, there are several DIY articles in the web that provide procedures in making your own DSC solar cell. 
One of the most popular sites is as follows:  http://www.solideas.com/solrcell/cellkit.html.